JPH03100655A - Defect correction equipment for emulsion masks, etc. - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a device for repairing defective parts of emulsion masks, etc., and more specifically, to the production of photoetching products and photoelectroforming products including the production of semiconductor devices. Emulsion mask, which is a type of photomask used during the process, or LCD, CC
This invention relates to an apparatus for removing defective parts of an organic film pattern (hereinafter referred to as an emulsion mask or the like) of a D color filter.

(Conventional technology) In recent years, patterns have become finer as ICs and LSIs have become more highly integrated, and patterns for semiconductor devices have become increasingly precise.
Although there is a trend toward higher quality, in addition to semiconductor devices, we also manufacture photoetching products such as shadow masks for color televisions, printed wiring boards, electrodes for various display tubes, marking lines for optical measuring instruments, meshes for photo tubes, and meshes for electron microscopes. Photoelectroforming products such as mesh for sieving and sieving also require high quality and precision.

Photofabrication technology has made possible fine precision processing that was impossible to achieve with conventional mechanical processing methods, but the photomasks used in this technology are required to have high image accuracy.

In photomasks that require such high image accuracy, it is necessary to correct minute defects that occur during the mask manufacturing process.

Currently, photomasks are divided into two types, emulsion masks and hard masks, depending on the material they are made of.Emulsion masks are made by coating the surface of a glass plate with a high-resolution photographic emulsion.

Generally, the sensitive materials for emulsion masks include silver salt materials and non-silver salt materials, and the film thickness thereof is usually about 2 to 6 microns.

On the other hand, a hard mask is made by forming a light-shielding metal thin film, such as chromium, iron oxide, tantalum, etc., to a thickness of about 0.1 μm on the surface of a glass plate by vapor deposition or sputtering.

Next, defects that occur during photomask manufacturing include pinholes and black spot scratches, and the methods for correcting pinholes and black spot scratches vary depending on the type of photomask, but we will explain black spot defects using specific examples. In the case of a hard mask, the general method is to mask the areas other than the defective areas with a photoresist or a substance that does not corrode the metal thin film, and then remove it with an etching solution.

If you want to remove a minute black spot defect of about 1μ, apply a positive resist, such as Tokyo Ohka's 0FPR resist, and then expose the resist over the defect to a mercury lamp light source focused to about 1μ, and then develop it. There is a method of removing the exposed metal thin film using an etching solution after removing the resist in the exposed area.

-4. In the case of an emulsion mask, the emulsion layer is thick and there is no suitable corrosive solution for metals, so the repair method is different from that of a hard mask. For example, one method for repairing sunspot scratches is to scrape them off with a sharp tip such as a utility knife, but this method does not require precision.
Or, it is limited to those in which the defective part is not connected to or adjacent to a non-defective part, and correction is not possible in the case of a photomask used for semiconductor manufacturing or microfabrication.

In order to eliminate this drawback, the present applicant has proposed a modification device for emulsion masks, etc., using an ultraviolet laser.
- Application number 149253 has been filed.

(Problems to be Solved by the Invention) In the above correction device, in order to correct a curved pattern, a variable aperture of a blade having protrusions or notches of different sizes or curvatures is used. To match the shape of the aperture to the shape of the defect, first, two-axis adjustment is required to select the protrusion or notch that matches the curvature of the curved pattern, and second, the aperture needs to be adjusted to match the defect size. Four axes of adjustment are required to open and close the four blades, and thirdly, a total of seven axes are required to adjust the axis of rotation of the entire aperture to match the direction of the defect.
Axis adjustment is required, and the device configuration is extremely complex.

(Means for Solving the Problems) The present invention has been made in view of the above points, and uses a complex device to remove defects in linear and curved patterns such as images on an emulsion layer such as an emulsion mask. The present invention provides a defect correction device such as an emulsion mask that can be easily removed without causing any damage.

In order to achieve this, in the present invention, the aperture is constituted by two aperture blades provided with a light transmitting part and a light shielding part for shaping the laser beam light, and these two aperture blades are A mechanism for stacking them and moving them both vertically and horizontally;
We constructed a correction device that has a mechanism that rotates the entire projection of an aperture image.

(Function) According to the structure described above, the defective part of the emulsion mask can be sublimated and removed by laser beam light, but the laser beam light is shaped by an aperture according to the shape of the defective part and irradiated. This has the advantage that only the defective part can be removed with high precision, and the non-defective part will not be damaged even if the defective part is continuous with or adjacent to the non-defective part.

Therefore, the shape of the laser beam can be easily shaped by moving the aperture blade using each mechanism and appropriately combining the transmitting light section and the light shielding section provided in each mechanism. The shape of the defect can be easily matched to the defect.

The shape of the transmitted light part and the light shielding part can be arbitrarily chosen, but it is preferable to provide a rectangular and circular transmitted light part on one aperture blade and a rectangular transmitted light part and a rectangular or circular light shielding part on the other aperture blade. By appropriately combining these two aperture blades, shapes surrounded by straight lines or curves can be freely created, and the shape of the laser beam can be easily shaped.

Further, the image rotation mechanism for rotating the projection of the aperture image may be one that rotates two apertures, or may be configured by an image rotator prism.

(Example) Hereinafter, embodiments of the device of the present invention will be described with respect to a concave surface.

In Figure 8, the ultraviolet laser beam (2) extracted from the laser oscillator (1) is transmitted to the beam expander (3).
The selective reflection mirror (4) reflects only the ultraviolet light, the aperture (5) shapes the beam image according to the shape of the defect, and the imaging lens (6) reduces and projects the emulsion. The area corresponding to the black spot defect on the surface of the silver emulsion layer of the mask (7) is irradiated.

In addition, the white light from the reference light lamp (8) is passed through a color filter.
(9), the aperture (5) is irradiated, and the aperture shape of the aperture (5) is projected as a colored image onto the emulsion mask (7) by the imaging lens (6).

Note that a condenser lens (not shown) may be provided in front of the reference light lamp (8) to make the illumination uniform.

The colored image of the aperture shape of the aperture (5) projected onto the emulsion mask (7) was placed at a symmetrical position with respect to the imaging lens (6) that forms the laser beam image and the emulsion mask (7). It is designed to be observed by a television camera (11) through an observation lens (10).

In addition, near the irradiation part of the emulsion mask (7) that is irradiated with laser light by the imaging lens (6), an air nozzle (12) is installed from one side, and in some cases,
A suction nozzle (not shown) is arranged at a symmetrical position with respect to the air nozzle (12) and the laser beam irradiation area, and blows air from the air nozzle (12) to the laser beam irradiation area on the emulsion mask (7). In some cases, this air is sucked by a suction nozzle (not shown).

Using a lens that can resolve visible light to ultraviolet light of the laser used without aberration as the imaging lens (6)
Since the optical design of the lens is extremely difficult and expensive, lenses designed to provide good resolution with laser ultraviolet light are used.

Further, an image formed by the opening shape of the aperture (5) is formed on the emulsion mask (7) by the light from the reference light lamp (8) using the imaging lens (6).
Since 6) uses a lens suitable for the ultraviolet region, the colored light filter (9) functions as a blue filter and uses the light on the ultraviolet side of the reference light lamp (8) as the reference light.

The observation lens (10) is aligned with the optical axis of the imaging lens (6) and is placed on the glass substrate (14) of the emulsion mask (7).
It is arranged so that the laser irradiated part of the emulsion layer (15) can be observed from the back side of the emulsion layer (15).
), (17).

The observation lens (10) has, with respect to the imaging lens (6),
Using a lens with good resolution in the visible light range, the epi-illumination system (16), (17) measures the state of the emulsion mask (7) in the laser irradiation section and the aperture image illuminated by the reference light lamp (8). ) and reference light lamp (8), and observe with a television camera (11).

The air nozzle (12) is arranged so as to blow air near the optical axis of the imaging lens (6) on the emulsion mask (7), and the air nozzle (12) is arranged so as to blow air near the optical axis of the imaging lens (6) on the emulsion mask (7), and is used to spray air from the emulsion layer (15) scattered by the laser irradiation at all times or during the laser beam irradiation period. ) Air is blown out to remove scattered objects.

The range of laser light irradiation is from several tens of micrometers to several hundreds of micrometers.
Since the range is so small, how much air is blown out? Il
It can be used in a sufficient amount and does not require high pressure.

Further, a suction nozzle (not shown) may be provided in place of the air nozzle (12), and in order to further enhance the effect, the suction nozzle may be provided at a position opposite to the air nozzle (12) and the laser irradiation section. Accordingly, it is also possible to use a configuration in which the particles removed by the laser beam are blown away and sucked at the same time.

The imaging lens (6) reduces and projects the beam image shaped by the aperture (5). The defective part is 1
The size of the aperture (5) is small, ranging from +na+ units to several tens of micrometers or several micrometers, and it is advantageous for the apparatus to manufacture the aperture (5) in an enlarged size and project the shaped beam image in a reduced size. The imaging lens (6) also weakens the energy density of the laser beam irradiated to the aperture (5) to an extent that does not damage the aperture (5).
The imaging lens (6
) also has the purpose of raising the image by reducing the projection.

Normally, the laser beam (2) output from the laser oscillator (1) has an intensity within the beam that is
The intensity is high in the center and decreases toward the periphery.

If this state remains, the processing speed by laser irradiation will be different between the center and the outer periphery, making uniform processing difficult. For this reason,
The beam is expanded by an optical system using a beam expander (3) so that the central part of the beam (2) with uniform intensity can be selectively used. The beam expander (3) is also used because it uses an expanded aperture and irradiates a relatively large area with the beam.

Note that if the beam (2) obtained from the laser oscillator (1) is relatively large and the intensity distribution is not extremely poor, sufficient results can be obtained without using the beam expander (3).

The laser oscillator (1) uses an excimer laser as a laser that oscillates ultraviolet light. Excimer lasers can emit several types of ultraviolet light depending on the type of halogen gas used.

Typical oscillation wavelengths are 308 nm (XeC1), 24
There are three types: 8 nm (KrF) and 198 nm (^rF), and the oscillation wavelength can be changed by gas exchange. Any of these three laser wavelengths can be used to remove the defective portion, but 248 nm is optimal because the transmittance of optical systems such as lenses becomes poor from about 200 nm.

The laser energy required to remove the defect is at the irradiation position.
The optimal energy density is about 5 to 50 J/c+fl, and the pulse energy of the laser oscillator (1) is 10
It is about 0 to 400 mJ/pulse.

The present invention provides an aperture (5
) consists of two aperture blades with a transmitting light section and a light shielding section for shaping the laser beam, and these two aperture blades are arranged one on top of the other, and each is arranged vertically and horizontally. It is equipped with a mechanism for moving and a mechanism for rotating the two aperture blades as a whole.

That is, FIG. 1 shows the aperture (5) according to the present invention.
), in which the aperture blade (51) and the aperture blade (52) are arranged one on top of the other on the aperture table (50), and each of these two blades (51) and (52) A position adjustment mechanism (53) so that it can be moved vertically and horizontally.
(54) is the aperture blade (51) and the position adjustment mechanism (55) (56) is the aperture blade (52)
is attached to.

Further, a rotation mechanism (57) for rotating the aperture blades (51, 52) as a whole is provided on the side of the aperture table (50).

For the position adjustment mechanisms (53) to (56), a mechanism capable of movement adjustment, such as a servo mechanism, is used. In addition, the rotation mechanism (57) is equipped with, for example, a servo motor (57), and by engaging a rack (58) formed around the periphery of the table (50) and a pinion gear (59), the entire table (50) can be rotated and adjusted. The aperture image can be rotated by

Next, FIG. 2(a) shows the shape of the aperture blade (51), and FIG. 2(b) shows the shape of the aperture blade (52).

The aperture blade (51) has a rectangular transmitted light section (
60) ... and a plurality of circular transmitted light parts (
61)... is provided. The aperture blade (52) includes one rectangular light-transmitting part (62), a rectangular light-shielding part (63), and a plurality of light-shielding parts (64) with different diameters.
...is provided.

Then, these two blades (51) and (52) are moved respectively by the above-mentioned adjustment mechanisms (53) to (57),
The laser beam is shaped by forming an opening to match the shape of the defect.

For example, in the case of a linear pattern defect, it is necessary to form a rectangular variable size aperture, which consists of the transmitted light part (60) of the aperture blade (51) and the transmitted light part (62) of the aperture blade (52). The position adjustment mechanism (53) moves each blade (51) (52) so that the two rectangular transmitted light parts (60) (62) are positioned on the laser beam optical axis. overlap to form an opening.

In order to match the size of the defect, the opening of the aperture (51) is adjusted by shifting the overlapping position of the two rectangular transmitted light sections (60) and (62) on the laser beam optical axis as shown in Figure 3. The size of the aperture (65) formed by overlapping the two aperture blades (51) (52) and the overlapping of the transmitting parts is the same as that of the rectangular transmitting light part (60). or (62)
By irradiating the aperture (5) with a laser beam, the beam passing through the aperture (5) is shaped to match the shape of the aperture. In the case of a defect with a curved pattern, select a circle that matches the curvature of the curve from the circular transmitted light part (61) of the aperture blade (51), and position it so that it is located at the center of the beam axis. Adjust the adjustment mechanism (53) (54) and select a light shielding part having a diameter larger than the diameter of the transmission circle selected from the aperture blade (51) from among the circular light shielding parts (64) of the aperture blade (52). Then, use the position adjustment mechanism (55) (56) to shift this position from the transmission circle (61) around the beam axis and position it as shown in Figure 4.
Adjust and do this.

In other words, the circular window (61) is replaced with a slightly larger circular lid (
64) and close it with a crescent-shaped opening (64).
6), the laser beam is shaped to match the shape of the defect in the curved pattern. In addition, in addition to the crescent-shaped hole, a rectangular light-transmitting part (60) and a circular light-shielding part (64) are combined to form a single-sided arc-shaped hole (67) as shown in Fig. 5. Furthermore, a circular light transmitting part (61) and a rectangular light shielding part (63
) to form a semicircular opening (68
) may be used to match the defective part.

The aperture (5) can be positioned at the defective part by using the position adjustment mechanisms (53) to (56) of these aperture blades (51) (52). This can be done by rotating the entire aperture (5) around the laser beam axis using a rotation mechanism (57) as an image rotation mechanism for rotating the image projection.

In addition, as another embodiment of the image rotation mechanism for rotating the aperture image, an image rotator prism (70) as shown in FIG. 7(a) is used, but the aperture blades (51) and (52) are not rotated. By fixing it to the image rotator prism (70) and rotating the image rotator prism (70),
A configuration may also be adopted in which the aperture image to be projected is rotated.

Further, a tab type prism (71) having the same function as the image rotator prism as shown in FIG. 7(b) may be used.

The aperture blades (51) and (52) can be formed by vacuum-depositing multiple layers of dielectric material for reflecting laser beam light onto a glass substrate.

That is, the aperture blade (51) is made by temporarily fixing a rectangular and circular metal plate on a glass substrate, vacuum-depositing a dielectric material thereon, and then peeling off the metal plate to form a rectangular and circular transparent part (60). (61), an aperture blade (51) is formed. Further, the aperture blade (52) is formed by temporarily fixing a rectangular metal plate and a metal plate having circular and rectangular windows on a glass substrate, and vacuum-depositing a dielectric material thereon.

In this case, a metal plate with a window is vapor-deposited on the part corresponding to the window to become a reflective layer and form the light-shielding parts (63) and (64), and the outer periphery of the part where the rectangular metal plate is pasted is vapor-deposited. The transparency of the glass remains as it is at the part where it is pasted,
It forms a rectangular transmitted light section (62).

The aperture blade (51) may be made of a metal plate with rectangular or circular holes, instead of a vapor-deposited glass substrate. It is also possible to form a transparent part, a light shielding part, and a light shielding part.

Next, an actual process for removing a defective portion of an emulsion mask or the like will be explained in accordance with the procedure using the apparatus of the present invention having the configuration as described above.

First, in FIG. 8, the transparent emulsion layer (15) is observed through the glass substrate (14) of the emulsion mask (7) using the observation lens (10).
15) Position the emulsion mask (7) so that the upper defect is located at the center of the field of view.

Next, the colored filter (9) from the reference light lamp (8)
Adjust the movement of each aperture blade (51) (52) while observing the aperture shape projected by the colored light transmitted through the aperture (5), and selectively adjust the transmitted light portion and the light blocking portion. Match the shape of the opening to the shape of the defect.

In this state, the laser beam (2) is emitted from the laser beam oscillator (1).
), the laser beam light (2) is expanded by the beam expander (3), passes through the selective reflection mirror (4), and is irradiated onto the aperture (5).
The laser beam light corresponding to the shape of the aperture produced by the blades (51) and (52) is reduced by the imaging lens (6) and irradiated onto the defective part on the emulsion mask (7), thereby scattering and removing the defective part.

For example, an emulsion mask (7) as shown in FIG.
The black spot defect (19) that is connected to the image area (18) on the emulsion layer (15) is removed as shown in FIG.

Furthermore, by using an ultraviolet laser, it is also possible to remove protruding defects (where the film thickness is locally high) that appear transparent under visible light.

The defective parts scattered by the laser beam are blown away and removed by an air nozzle (12) as shown in FIG.

In addition to the above-mentioned oscillation wavelength, the excimer laser has three oscillation wavelengths.
51nm (XeF), 222nm (KrC1), 1
57 nm (F z), which can also be used as a laser source, and wavelengths around 200 nm or less can be realized by using a reflective optical system instead of a glass lens.

(Effects of the Invention) The apparatus of the present invention can be applied not only to a silver salt emulsion mask using a silver salt emulsion dry plate, but also to a diazo photosensitive solution (a diazo compound mixed with a colloidal substance such as gelatin) on the surface of a glass plate, for example. A non-silver salt emulsion is produced by using a non-silver salt emulsion dry plate coated with a photosensitive liquid (photosensitive liquid), printing an image on it to form an image area made of an organic polymer film, and dyeing the image area. It can also be applied to mask correction, and is also useful for correction of organic film patterns of color filters for LCDs or CCDs.

In addition, with the configuration of the present invention, an aperture that forms a laser beam in the shape of a defect can be created using two aperture blades and five-axis adjustment for defects in various linear or curved patterns. This has the effect that the aperture can be manufactured with a simpler configuration than before.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an embodiment of the device of the present invention, and FIG.
) (b) is a plan view of the aperture blade, Figures 3 to 6 are explanatory diagrams of the state in which an opening is formed, and Figure 7 (a)
)(b) is a perspective view of an image rotator prism and a perspective view of a tab type prism, FIG. 8 is a schematic diagram of a defect correction device, FIG. 9 is a plan view of an emulsion mask having a defect, and FIG. 10 is a perspective view of a defect. 3A and 3B each represent a plan view of the emulsion mask from which . 5152...Aperture blade 53-56...
...Position tone! ff mechanism 57...Rotating mechanism 60-62...Transmitting light section 63.64...Shading section 65-68...Opening hole 70...Image rotator prism 71・・・
...Tab type prism Figure 1

Claims (4)

[Claims] (1) In a defect repair device that removes the defect by shaping laser beam light using an aperture according to the shape of the defect and irradiating the defect, the aperture is a transmitting light part or a light shielding part for shaping the laser beam light. It is a stack of two aperture blades each having one or both of these, and is equipped with a position adjustment mechanism that moves each aperture blade in the vertical and horizontal directions, and an image rotation mechanism that rotates the projection of the aperture image. A defect correction device for emulsion masks, etc., characterized by: (2) One of the two aperture blades is provided with a rectangular and circular transmitted light section, and the other is provided with a rectangular transmitted light section and a circular or rectangular light shielding section. The apparatus for correcting defects such as emulsion masks according to claim (1). (3) The defect correction device for an emulsion mask or the like according to claim 1 or 2, wherein the image rotation mechanism that rotates the projection of the aperture image is a mechanism that rotates an aperture blade. (4) The defect correction device for an emulsion mask or the like according to claim 1 or 2, wherein the image rotation mechanism for rotating the projection of the aperture image is an image rotator prism.